Add handling of Linked Data Signatures in payloads (#4687)

* Add handling of Linked Data Signatures in payloads

* Add a way to sign JSON, fix canonicalization of signature options

* Fix signatureValue encoding, send out signed JSON when distributing

* Add missing security context

1 files changed, 6 insertions, 2 deletions

diff --git a/app/services/batched_remove_status_service.rb b/app/services/batched_remove_status_service.rb
index e6c8c9208..c90f4401d 100644
--- a/app/services/batched_remove_status_service.rb
+++ b/app/services/batched_remove_status_service.rb
@@ -138,10 +138,14 @@ class BatchedRemoveStatusService < BaseService
   def build_json(status)
     return @activity_json[status.id] if @activity_json.key?(status.id)
 
-    @activity_json[status.id] = ActiveModelSerializers::SerializableResource.new(
+    @activity_json[status.id] = sign_json(status, ActiveModelSerializers::SerializableResource.new(
       status,
       serializer: ActivityPub::DeleteSerializer,
       adapter: ActivityPub::Adapter
-    ).to_json
+    ).as_json)
+  end
+
+  def sign_json(status, json)
+    Oj.dump(ActivityPub::LinkedDataSignature.new(json).sign!(status.account))
   end
 end